Hole detector and defect finder for knitting machines



- I E. VOSSEN Dec. 24, 1957 HOLE DETECTOR AND DEFECTFINDER FOR KNITTING MACHINES File d Sept. 12, 1955 INVENTOR EDWARD VOSSEN.

ATTORNEY FIG. 3.

United States Patent HOLE DETECTOR AND DEFECT FINDER FOR KNETTING MACHINES Edward Vossen, Malverne, N. Y., assignor to Stop-Motion Devices Corp., Brooklyn, N. Y.

Application September 12, 1955, Serial No. 533,673

Claims. (Cl. 66166) This invention relates to a hole detector for knitting machines.

Hole detectors for circular and other knitting machines are known. The problem is not Whether or how these hole detectors operate but rather when or where. Holes and other like defects or imperfections are formed in the immediate vicinity of the needles. Yarn may break or terminate and an imperfection will accordingly be formed in the course of the knitting operation and immediately upon the failure of the yarn to reach a given needle.

Hole detectors are conventionally located a substantial distance away from the needle. A distance of six to twelve inches is not unusual. The placing of hole detectors is not an arbitrary procedure but is rather dictated by the nature and dimensions of the hole detectors and the extent to which the knitted fabric is exposed to engagement with them. The greater the distance between the needles and the hole detectors, the greater is the loss of material since a hole which is formed at the needles is not detected until an additional six to twelve inches of material is produced. In the case of relatively expensive material, where each foot may have a value of several dollars, it is obvious that such losses can reach serious proportions.

It is the principal object of this invention to provide a hole detector of the character described, which may be so positioned on a knitting machine that it is engageable with the knitted fabric immediately adjacent the needles. Virtually the moment a defect is formed in the knitted fabric, said defect is detected by the hole detector herein claimed. The loss of defective fabric is held to a minimum.

The present invention relates mainly, but not exclusively, to circular knitting machines and for purposes of illustration the invention will be described and shown solely in connection with circular knitting machines but it will clearly be understood that this is not intended to limit the scope and application of the present invention.

The hole detector herein claimed is a relatively long, narrow, thin device which may be inserted into the space between the circular bed or cylinder of the machine and the tube of knitted fabric which extends therethrough. As a practical matter, it is only the thickness of the cylinder wall which separates the hole detector herein claimed from the place where the defects are formed. Approximately one inch from the place where a hole is formed, said hole is detected.

An important object of this invention is the provision of a hole detector of the character described in which the probe or feeler is movable in two directions upon engaging a hole in the fabric, said probe or feeler being pivotally movable in the general direction of movement of the fabric (or cylinder) in a circular path, and being also retractable in downward direction to disengage said hole promptly upon signaling its presence to the stop motion mechanism. This prevents injury to the hole detector and further damage to the fabric.

A further object of this invention is the provision of a unique resetting mechanism which simultaneously restores the probe or feeler to operative position and resets the switch mechanism.

The invention is illustrated in the accompanying drawing in which:

Fig. l is a vertical section through the cylinder and ring of a typical circular knitting machine, showing the hole detector herein claimed supported by said ring and projecting upwardly within the cylinder into engagement with the knitted tube.

Fig. 2 is a side view of the hole detector herein claimed.

Fig. 3 is a vertical section on the line 33 of Fig. 2, showing the hole detecting mechanism.

Fig. 4 is another vertical section on the line 44 of Fig. 2 showing the switch mechanism.

Fig. 5 is an enlarged section on the line 5-5 of Fig. 3.

Fig. 6 is a transverse section on the line 66 of Fig. 2.

The circular knitting machine illustrated in the drawing is provided with a circular bed or cylinder 10 surrounded by a ring 12. The needles 14 are situated around the cylinder 10 and they are actuated in conventional manner by conventional means. It will be observed that the top edge 16 of cylinder 10 slopes downwardly and inwardly toward the center of the cylinder. The knitted fabric tube 18 moves down said sloping edge 16 and through the cylinder. A small annular space is provided between the inner wall or surface 20 of cylinder 10 and said knitted tube 18. Thus far the construction is completely conventional.

A bracket 30 is provided to support the hole detector 32 herein claimed. This bracket includes a C-clamp 34 or the like, having one or more set screws 36, adapted to engage ring 12. Obviously, said C-clamp may be placed in any desired location about the peripheral edge of said ring 12, and it may thereby be placed in an out-of-theway location. Bracket 30 is provided with a horizontal arm 38 which extends radially inwardly toward the center of the machine. It supports a bar 40 which is secured thereto by means of screws 42. These screws project through longitudinally extending slots 44 in bar 40 and it will be understood that said bar may be slidably adjusted on arm 33 either radially inwardly or radially outwardly of the machine. A block 46 is affixed to the inner end of bar 40 to support the hole detector 32. It will be observed that a vertical slot or channel 48 is formed in block 46 and in the inner end of bar 40. Vertical bar 50 of hole detector 32 is slidably disposed in said channel 48. A plate 52 is secured to the inner faces of block 46 and arm 40 by means of screws 54. This plate bears against vertical bar 50 and clamps it in place in said channel 48 at any selected vertical position therein.

The probe or feeler 60 projects upwardly through a longitudinally extending slot 62 formed in vertical bar 50. There is a crosspin 64 on probe 60 and this crosspin extends through a pair of registering slots formed in the sides of vertical bar 50. These slots are shown in Figs. 2 and 3 and they are identified by the reference character 66. From the foregoing description it will be understood that the probe 60 is adapted to engage in pivotal movement about the axis of pin 64 and it is also adapted to engage in longitudinal movement longitudinally of slots 66. A pair of plates 68 may be placed against the sides of vertical bar 50 to cover slots 66 and thereby to prevent foreign matter from entering. Screws 70 may be used to secure these plates to the vertical bar.

The lower end of probe 60 is pivotally secured by means of a pin to the bifurcated yoke 82 of a bar 84. A crosspin 86 is secured to the lower end of said bar 84 and this crosspin projects through registering slots 88 tached to the vertical bar and it enables "bar 84 to engage in pivotal movement about the axis of pin 86 and also in longitudinal movement longitudinally of slots 88. A pair of side plates 90 may be secured to the sides of vertical bar 50 by means of screws 92 in order to cover the slots 88 and to prevent the entry of foreign matter.

It will be observed that probe 60 and bar84 are disposed in aligned grooves, groove 62 receives the probe and groove 94 receives bar 84. Between the two grooves and communicating therewith is a chamber 96 and a pair of shoulders 98 is provided between said chamber and groove 94. The lower end of the probe and the upper end of bar 84 project into said chamber. A plate 100 is slidably mounted on bar 84 and a compression spring 102 is also mounted on said bar between said plate 100 and the bifurcated yoke 82. Plate 100 bears against shoulder 98 under the influence of said spring and the spring acts to urge bar 84 and probe 60 upwardly. To guide the probe and to resiliently retain it in longitudinal position in vertical bar 50, a ball 106 is provided and it will be seen that said ball is retained in a cavity 108 formed in said vertical bar 50. A spring plate 110, secured to the side of said vertical bar by a screw 112, engages the ball 106 and presses it against one edge of probe 60, thereby tending to hold the probe in its said longitudinal, operative position. In this position, it is longitudinally movable in said vertical bar and urged upwardly by the spring 102 into engagement with the knitted tube 18 immediately adjacent the line of junction between the inner wall 20 and the sloping upper edge 16 of cylinder 10.

When relative angular movement takes place between the knitted tube and the cylinder 10, there is relative movement between the probe and the knitted tube. A hole that may be formed in said knitted tube will be encountered by the probe and said probe will enter the hole under the urging of said spring 102. Further relative movement will trip the probe and cause it to slip into its diagonal position indicated by the interrupted lines in Fig. 2. This is in the nature of a toggle action wherein once the probe slips past the ball 106, spring 102 will act upon the probe to urge it into its said canted or dotted line position. It will be clear from an examination of Fig. 2 that the probe is not only in canted position, but also in retracted position. That is, it is drawn downwardly as well as pivotally and it thereby is enabled to clear the fabric. In that brief moment between the time the hole is detected and the machine is stopped, further damage might be caused to the fabric and possible damage to the hole detector were it not for this retractive movement which disengages the probe from the fabric.

It is this movement of the probe which causes actuation of the switch. It will be seen in Fig. that a transverse hole 120 is formed in the vertical bar 50 and that slidably mounted in said transverse hole is a pin 122 which is made of fiber or other dielectric material. One end of said pin 122 is engageable by the probe 60 when said probe is in its longitudinal position, as shown in Fig. 5. The opposite or outer end of pin 122 engages a leaf-type of contact member 124. This leaf contact member is supported between insulating blocks 126 and 128 respectively which are secured to each other and to the vertical bar 50 by means of screws 130. There is, of course, no contact between said screws and the leaf contact member 124. A conductor 132 and a wire 134 connect the leaf contact member 124 to the stop motion mechanism. There is a second leaf contact member 136 which faces leaf contact member 124 and abuts the side of vertical bar 50. It is secured to said vertical bar by the same screws 130 which fasten insulating blocks 126 and 128 to said vertical bar.

It will be noted that a contact button 138 is secured to leaf 136 and a second contact button 140 is secured to leaf 124. The two contact buttons register with each other and they are adapted to make contact with each other, thereby closing the circuit between the two leaf contact members 124 and 136. The spring tension in. leaf 124 normally holds its contact button in engagement with contact button 138 and the switch may therefore be termed a normally closed switch.

Leaf contact member 136 is grounded through the vertical bar 50. The stop motion mechanism is also grounded. All that need be done to actuate the stop motion mechanism is to permit contact button 140 to engage contact button 138. When the probe is in its longitudinal position, it pushes the pin 122 against the leaf contact member 124 and holds the contact button 140 out of engagement with contact button 138. When the probe encounters a hole in the fabric, the probe is swung to its dotted line position in Fig. 2 and thereby disengages the pin 122. This frees the leaf contact member 124 for inward movement in the direction of the leaf contact member 136 and enables the contact button 140 to engage the contact button 138, thereby closing the circuit to the stop motion mechanism and causing it to stop the machine.

After a hole is detected and its cause remedied or corrected, it is necessary to return the probe to its longitudinal, probing position. This is accomplished by means of a pair of finger pieces which are secured to a pair of bars 152 that are slidably disposed for longitudinal movement in either direction in a pair of channels 154 formed in the sides of the vertical bar 50. These bars 152 are secured at their lower ends to a block 156 and said finger pieces 150 are also secured to said block. It is by this means that the lower portions of bars 152 are confined to the channels 154. The upper ends of said bars 152 are confined to channels 154 by means of plates 90 above mentioned. Consequently, bars 152 are free to move longitudinally through said channels 154 but they are prevented from leaving said channels. A crosspin 158 is secured to the upper ends of bars 152. This crosspin is adapted to move through slot 88 above mentioned when the two bars 152 are moved longitudinally in their respective channels 154. It will now be observed that bar 84 has a laterally extending end portion 160 at its lower end and that said end portion extends across the path of crosspin 158. There is a little recess 162 in said end piece 160 to receive crosspin 158 when the two bars 152 are pulled downwardly. This is done when the probe is in its canted position and it is desired to return it to its vertical position. Finger pieces 150 are engaged by the fingers and pulled downwardly against the action of a spring 164 to draw the two bars 152 downwardly and thereby to bring the crosspin 158 into engagement with the laterally offset end portion 160 of bar 84. Said bar will now be tilted back to longitudinal position and it will at the same time be pulled downwardly against the action of spring 102. This will have the effect of returning the probe to its longitudinal position and at the same time to retract it temporarily. When the finger pieces 150 are released, spring 102 will push the probe upwardly into probing position and spring 164 will return the two bars 152 to elevated position with crosspin 158 out of engagement with the laterally extending end portion 160 of bar 84. The hole detector herein claimed is now reset and ready to detect the next hole that may be formed in the fabric.

The foregoing is illustrative of a preferred form of this invention and it will be understood that this preferred form may be modified and other forms may be provided within the broad spirit of the invention and the broad scope of the claims.

I claim:

1. In a circular knitting machine having a cylinder disposed on a vertical axis and needles on said cylinder to knit a fabric tube which extends from the needles, across the top of the cylinder and then down into and through the cylinder a spaced distance from the inner wall of the cylinder, a hole detector for detecting a hole in said knitted fabric tube, said hole detector being mounted substantially in vertical position between the inner wall of said cylinder and said knitted fabric tube, and being provided with a pointed probe which extends upwardly therefrom for engagement with the knitted fabric tube at a point adjacent the top of the cylinder, said probe being movable upwardly into engagement with said knitted fabric tube and being movable downwardly and pivotally about a horizontal axis out of engagement with said knitted fabric tube, said probe being movable from its said engaging position to its said non-engaging position when it encounters and engages a hole in said knitted fabric tube, there being relative lateral movement between said knitted fabric tube and said probe when the machine is in operation.

2. A hole detector in accordance with claim 1, having a bracket supporting it from the frame of the knitting machine, said bracket comprising a clamp which clamps to said frame, a horizontal arm supported by said clamp below the cylinder, at second horizontal arm adjustably secured to the first horizontal arm for adjustment in a horizontal plane, and a clamp on said second horizontal arm which adjustably secures the hole detector thereto, said hole detector being vertically adjustable relative to the second horizontal arm to adjust the position of its probe relative to the knitted fabric tube.

3. A hole detector in accordance with claim 1, having a vertically extending housing and a longitudinally eX- tending slot formed in said housing to receive the probe, said housing having longitudinally extending slots formed therein and said probe having a crosspin which extends through said slots, whereby the probe is adapted to engage in pivotal movement about the axis of said crosspin and in vertical movement longitudinally of said slots, a springurged toggle member being connected to the lower end of said probe to normally hold the probe in vertical position in spring-urged engagement with the knitted fabric tube, except when the probe engages a hole in said knitted fabric tube and is thereby displaced from its vertical position,

whereupon said toggle member urges the probe into pivoted position about the axis of said crosspin and into retracted position longitudinally downwardly along said slots.

4. A hole detector in accordance with claim 1, wherein the probe is pivotally mounted in a housing, a pair of contact members mounted on said housing, one of said contact members being grounded to the housing and the other being insulated therefrom, both contact members being connected to a grounded stop motion mechanism, one of said contact members being spring urged into engagement with the other contact member, a pin slidably mounted in said housing between the spring-urged contact member and the probe, whereby the probe holds the pin against the spring-urged contact member to hold said spring-urged contact member out of engagement with the other contact member when the probe is in vertical position in said housing, and whereby the probe releases the pin when it moves to pivoted position and thereby releases the springurged contact member for engagement with the other contact member to close the circuit to the stop motion mechanism.

5. A hole detector in accordance with claim 1, comprising a vertically disposed housing slotted to receive the probe in vertical position therein, said probe being pivotally secured to said housing for pivotal movement in the slot from vertical position to canted position, a spring urged toggle member connected to said probe and resiliently holding it in either of said positions, and a manually operated retracting means connected to said toggle member for pivoting the probe from canted to vertical position.

Rogow Feb. 20, 1951 Vossen Oct. 9, 1951 

